Projector

ABSTRACT

A projection-type display apparatus in accordance with the invention reduces the margin formed around the image forming range of the light valves, and forms a bright projected image. Emitted light from a light source lamp unit of a projection-type display apparatus illuminates liquid crystal light valves of each color via an integrator optical system. First and second lens plates of an integrator optical system that serves as a uniform illuminating optical system are disposed such that the attachment position thereof is capable of fine adjustment in a direction vertical to the optical axis. By performing fine adjustment of the attachment position of these, the forming position of the illumination range B can be adjusted to include the image forming range A of the liquid crystal light valves. Accordingly, there is no need to provide a wide margin around the image forming range A, taking shifting of the forming position of the illumination range B into consideration. Thus, efficient usage of the illumination light can be increased, thereby improving the brightness of the projected image.

This is a Continuation of application Ser. No. 08/912,566 filed Aug. 18,1997 now U.S. Pat. No. 6,142,634 . The entire disclosure of the priorapplication(s) is hereby incorporated by reference herein in itsentirety.

BACKGROUND OF THE INVENTION

1. Field of Invention

The invention relates to a projection-type display apparatus whichmodulates light emitted from a light source in accordance with imagesignals using modulation devices such as liquid crystal light valves orthe like, and performs enlarged projection of the light flux followingmodulation upon a screen via a projecting lens. More particularly, theinvention relates to a structure for a projection-type display apparatusof such a type whereby the image formation range of the modulatingdevices can be illuminated in an appropriate manner.

2. Description of Related Art

A conventional projection-type display apparatus which forms modulatedlight flux in accordance with image signals using liquid crystal lightvalves and performs enlarged projection of the modulated light flux on ascreen is disclosed in Japanese Unexamined Patent Publication No.3-111806. The projection-type display apparatus disclosed in this PatentPublication is, as shown in FIG. 14, provided with an integrator opticalsystem 923. The integrator optical system 923 has two lens plates 921and 922 for uniform illumination of the image formation range of theliquid crystal light valve 925. The liquid crystal light valve 951serves as the modulation device of the light emitted from the lightsource.

In FIG. 14, the single light flux emitted from the light source lampunit 8 is separated into a plurality of intermediate light fluxes bylenses 921 a of the first lens plate 921. The light flux is superimposedon the liquid crystal light valve 951 via lenses 922 a of the secondlens plate 922.

Regarding projection-type display apparatuses of the type illustrated inFIG. 14, problems occur when the image formation range of the liquidcrystal light valve 951 cannot be illuminated accurately. These problemsinclude a reduction in the brightness of the image projected on theprojection surface, or the creation of shadows at the edge of theprojected image. Accordingly, as illustrated in FIG. 15, a certainmargin M is secured around the image formation area A of the liquidcrystal light valve 925, depending on various factors including thepositioning precision of the liquid crystal light valve 951 and the lensplates 921 and 922 of the integrator optical system 923, the margin oferror of the focal distance and so forth of the lenses 921 a and 922 aof each of the lens plates, and the positioning precision and the likeof other optical components disposed on the optical path. In otherwords, the image formation area A of the liquid crystal light valve 951is sized to be distinctly smaller than the illumination range B of lightemitted by the light source, so that even in the event that theillumination range B is shifted vertically or horizontally due to thepositioning precision of the above-described components, the imageformation range A does not extend beyond the illumination range B. Thisstructure avoids problems such as the reduction of the brightness of theimage projected on the projection surface, or the creation of shadows atthe edge of the projected image. Thus, simply increasing the margin M issufficient to deal with a wide margin of error in positioning of theabove-described components.

On the other hand, in order to increase the brightness of the projectedimage, it is necessary to increase the usage efficiency of the lightwhich is illuminating the liquid crystal light valve 925. However, theproblem occurs that when the margin M is increased to deal with a widemargin of error in positioning of the above-described components, theusage efficiency of the separated light decreases, and the projectedimage becomes dark. Accordingly, from this perspective, it is desirablethat the margin formed around the display range of the liquid crystallight valve be as narrow as possible. However, if the margin is made tobe narrow, the illumination range misses the image formation range ofthe liquid crystal light valve, as described above, so that shadows maybe formed at the edge of the projected image.

SUMMARY OF THE INVENTION

It is therefore an object of the invention to provide a projection-typedisplay apparatus wherein the margin formed around the image formingrange of the liquid crystal light valve is small, and at the same time,capable of increasing the brightness of the projected image withoutforming shadows at the edge of the projected image.

In order to solve the above-described problems, a first projection-typedisplay apparatus in accordance with the invention includes a lightsource; a modulating device for modulating light flux emitted from thelight source in accordance with image signals; and a projecting devicefor performing enlarged projection of the light flux modulated by themodulating device upon a projection surface; wherein an integratoroptical system having a first lens plate and a second lens plate thatinclude a plurality of lenses arrayed in matrix-form is placed in theoptical path between the light source and the modulating device; andwherein at least one of the first and second lens plates is arranged sothat an attachment position thereof is adjustable in a directionintersecting the optical axis.

According to the structure described above, the invention is capable ofincreasing the usage efficiency of the light which is illuminating themodulating device, and the projected image can be made to be brighter.Also, fine adjustment of the illumination area of the modulation devicecan be performed so that the image forming range is positioned withinthe illumination area, which avoids problems such as the reduction ofthe brightness of the image projected upon the projection surface, orthe creation of shadows at the edge of the projected image, even if themargin formed around the image forming range of the modulation device ismade to be small.

In other words, subsequent to mounting the various components of theoptical system, the image forming range of the modulation device isilluminated using the integrator optical system, and in the event thatthe illumination range is not within the image forming range of themodulation device, the attachment position of the first lens plate orthe second lens plate of the integrator optical system is subjected tofine adjustment, so that the image forming range of the modulationdevice can be brought to be completely within the illumination range.Accordingly, the margin formed around the image forming range of themodulation device can be reduced and still handle the offset between theillumination range and the image formation range caused by the margin oferror in the positioning of optical parts.

Further, the reflecting device for bending the optical path is sometimesprovided on the optical path extending from the light source to themodulation device of projection-type apparatuses. In such cases, anymargin of error in the attachment angle of the reflecting device maycause the illumination range to be offset from the image formation rangeof the modulating device. Accordingly, it is desirable that theattachment angle of the reflecting device mounted to his position alsobe adjustable relative to the incident optical axis.

Also, the above-described first embodiment of the projection-typedisplay apparatus can similarly be applied to projection-type displayapparatuses capable of protecting color images. In other words, theinvention can similarly be applied to a projection-type displayapparatus that includes a color separating optical system for separatingthe light emitted from the light source into light flux of each color, aplurality of the modulating devices for modulating the light flux ofeach color separated by the color separating optical system, and a colorsynthesizing system for synthesizing the light flux of each colormodulated by the plurality of the modulating devices, wherein themodulated light flux synthesized by the color synthesizing system isprojected on a projecting surface via the projecting device.

With such projection-type display apparatuses capable of projectingcolor images, reflecting devices for bending the optical path aresometimes also provided on the optical path from the color separatingoptical system to at least one of the modulation devices. In such cases,the attachment angle of any of the reflecting devices may cause theillumination range to be offset. Accordingly, it is desirable that theattachment angle of the reflecting device mounted to this position bealso adjustable relative to the incident optical axis.

It is most advantageous, from the perspective of apparatus constructionand from the perspective of precision of position adjustment of theillumination range as to the modulation device to make the attachmentangle of the reflecting means mounted to the position closest to themodulating device to be adjustable.

Also, using reflecting type modulation devices for the modulation, andmanufacturing the color separating optical system and the colorsynthesizing optical system as a single optical system, shortens theoptical path, which reduces the size of the projection-type displayapparatus.

A second projection-type display apparatus in accordance with theinvention is described below. The second projection-type displayapparatus in accordance with the invention includes a light source; afirst optical component for splitting the light fluxes emitted from thelight source into a plurality of intermediate light fluxes; a secondoptical component disposed in the proximity of the position at which theintermediate light fluxes are focused; a modulating device formodulating light emitted from the second optical component; and aprojecting device for performing enlarged projection of the light fluxmodulated by the modulating device on a projection surface; wherein thesecond optical component includes a focusing lens array for focusingeach of the plurality of intermediate light fluxes divided by the firstoptical component; a polarization converting device which spatiallysplits each of the plurality of intermediate light fluxes focused by thefocusing lens array into P-polarization light flux and S-polarizationlight flux, and emits the P-polarization light flux and S-polarizationlight flux with the polarization direction of one matching thepolarization direction of the other; and a combining lens forsuperimposing the light fluxes emitted from the polarization convertingdevice; wherein at least one of the first optical element and the secondoptical element is arranged so that the attachment position thereof isadjustable in a direction intersecting the optical axis.

The first optical component is equivalent to the aforementioned firstlens plate, and the combining lens of the second optical component isequivalent to the aforementioned second lens plate.

The second projection-type display apparatus in accordance with theinvention includes a focusing lens array and polarization conversiondevice in addition to the structure of the first projection-type displayapparatus. Accordingly, the same effects as those of the firstprojection-type display apparatus are obtained, and in addition, abright projected image can be obtained, since both polarized lightfluxes can be used without waste, by using the polarization conversiondevice. Also, the focusing lens array can be used to efficientlyintroduce intermediate light fluxes to the focusing lens array, and fromthis perspective also, a bright projected image can be obtained.

Integrating the focusing lens array, the polarization converting device,and the combining lens, reduces the loss of light between these opticalcomponents, which further improves the usage efficiency of light.

Also, as with the aforementioned first projection-type displayapparatus, the second projection-type display apparatus in accordancewith the invention also allows the reflecting device to be disposed onthe optical path that extends from the light source to the modulationdevice for bending the optical path, having a structure capable ofprojecting color images, the reflecting device to be disposed on theoptical path between the color separating optical system and themodulation device in projection-type display apparatuses capable ofprojecting color images and adjusting the angle thereof, which enablesthe attachment angle of the reflecting device positioned closest to themodulating device to be adjustable, and using a reflecting typemodulation device as the modulation device. The same effects can beobtained as when using these structures with the first projection-typedisplay apparatus.

Also, the invention can be applied to projection-type displayapparatuses which are not provided with integrator optical systems. Insuch cases, the attachment angle of the reflecting device disposed inthe optical path that causes positional change of the illumination rangeshould be adjustable. Also, in this case, the same effects can beobtained as with the aforementioned first projection-type displayapparatus. Further, the invention can be applied to projection-typedisplay apparatuses capable of projecting color images which are notprovided with integrator optical systems, wherein such cases, theattachment angle of the reflecting device disposed in the optical pathbetween the color synthesizing system and the modulating device shouldbe adjustable so that the same effects can also be obtained as with theaforementioned first projection-type display apparatus.

Now, with the first projection-type display apparatuses in accordancewith the invention, in order to make the attachment position of at leastone of the first and second lens plates to be adjustable in thedirection intersecting the optical axis, an adjustment mechanism shouldbe provided at that end. Examples of arrangements for such an adjustmentmechanism include a first adjustment mechanism for adjusting theaforementioned first lens plate in a first direction orthogonallyintersecting the optical axis, and a second adjustment mechanism foradjusting the aforementioned second lens plate in a second directionorthogonally intersecting the aforementioned optical axis and theaforementioned first direction.

An adjusting mechanism for adjusting the attachment position of the lensplate in a predetermined direction can include a spring disposed at afirst side of the lens plate for pressing the first side; and a screw ata second side of the lens plate opposing the first side thereof, forpressing the second side. By employing such an adjusting mechanism, thelens plate can be moved in the predetermined direction simply bytightening and loosening the screw, which facilitates simple adjustmentof the attachment position of the aforementioned lens plate.

Regarding the adjusting mechanism using the spring and screw, uniformmovement of the lens plate can be facilitated with a small number ofparts, by using a leaf spring for the spring and arranging the screw topress the approximately center portion of the second side of the lensplate.

Also, regarding the second projection-type display apparatus inaccordance with the invention, in order to make the attachment positionof at least one of the first optical component and second opticalcomponent to be adjustable in the direction intersecting the opticalaxis, an adjustment mechanism should be provided at that end. In thecase of the second projection-type display apparatus in accordance withthe invention, it is preferable that the focusing lens array, thepolarization converting device, and the combining lens be integrated,and this integrated apparatus moved by a single adjusting device. Thisis because such an arrangement enables simultaneous adjustment of theattachment position of the three optical components.

As for the adjustment mechanism provided to the second projection-typedisplay apparatus in accordance with the invention, an adjustmentmechanism can be used that is the same as that of the aforementionedfirst projection-type display apparatus. For example, an arrangement canbe used that includes a first adjustment mechanism for adjusting theaforementioned first optical component in a first direction orthogonallyintersecting the optical axis, and a second adjustment mechanism foradjusting the aforementioned second optical component to a seconddirection orthogonally intersecting the optical axis and theaforementioned first direction. Also, the adjusting mechanism foradjusting the attachment position of the optical component in thepredetermined direction can include a spring disposed at a first side ofthe optical component for pressing the first side; and a screw disposedat a second side of the optical component opposing the first sidethereof, for pressing the second side. Further, the adjusting mechanismemploying a spring and screw can include a leaf spring used for thespring and the screw can be arranged so as to press the approximatelycenter portion of the second side of the lens plate.

Further, regarding projection-type display apparatuses which are notprovided with integrator optical systems, in order to make theattachment angle of the reflecting device positioned in the optical paththat causes positional change of the illumination range to beadjustable, an adjustment mechanism should be provided at that end.Regarding such adjustment mechanisms, in the event that theprojection-type display apparatus is provided with at least theaforementioned light guide for storing the aforementioned colorseparation system and the aforementioned reflecting device, anarrangement can be used that includes a holder plate which holds thereflecting device and is rotatably supported by the light guide, a screwfor adjusting the angle of the reflecting device, and a spring forsupporting the holder plate as to the light guide. Such an adjustingmechanism arrangement enables simple changing of the attachment angle ofthe reflecting device, simply by adjusting the amount of screwing by thescrew.

Also, regarding projection-type display apparatuses capable ofprojecting color images which are not provided with integrator opticalsystems, in order to make the attachment angle of the reflecting devicepositioned in the optical path between the color synthesizing system andthe modulating device to be adjustable, an adjustment mechanism shouldbe provided at that end. As described above, with such a projection-typedisplay apparatus, making the attachment angle of the reflecting devicemounted at the position closest to the modulating device to beadjustable is most advantageous, from the perspective of apparatusconstruction and from the perspective of precision of positionadjustment of the illumination range as to the modulation device.Regarding such adjustment mechanisms, in the event that theprojection-type display apparatus is provided with at least theaforementioned light guide for storing the aforementioned colorseparation system and the aforementioned reflecting device, anarrangement can be used that includes a holder plate which holds thereflecting device and is rotatably supported by the light guide, a screwfor adjusting the angle of the reflecting device, and a spring forsupporting the holder plate as to the light guide.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the exterior of the projection-typedisplay apparatus in accordance with the invention.

FIG. 2(A) is a broken away top elevational view showing the interior ofthe projection-type display apparatus, and FIG. 2(B) is a broken awayside elevational view thereof.

FIG. 3 is a broken away elevational view showing an extracted view ofthe optical unit and projecting lens unit.

FIG. 4 is a schematic drawing showing the optical system which isincorporated in the optical unit.

FIGS. 5(A)-(D) are model illustrations showing the relationship betweenthe illumination range from the integrator optical system, with thedisplay range of the liquid crystal light valve.

FIGS. 6(A) and 6(B) are each schematic cross-sectional views showing amechanism for making fine adjustment of the attachment position of thelens plate to the left and right.

FIGS. 7(A) and 7(B) are explanatory diagrams showing the change in formof the illumination range of the integrator optical system from thereflecting surface of the reflecting device.

FIGS. 8(A)-(C) show a mechanism for performing fine adjustment of theattachment angle of the reflecting mirror, wherein FIG. 8(A) is anexplanatory diagram of the holder plate, FIG. 8(B) is a plan view of themechanism for performing fine adjustment, and FIG. 8(C) is across-section diagram of the fine adjustment mechanism.

FIG. 9 is a schematic plan diagram of the principal components ofanother example of an optical system of the projection-type displayapparatus in accordance with the invention.

FIG. 10(A) is a perspective view showing the polarization splitting unitarray shown in FIGS. 7(A) and 7(B), and FIG. 10(B) is an explanatorydiagram showing the splitting operation of polarization light flux bythe aforementioned polarization splitting unit array.

FIGS. 11(A) and 11(B) are schematic cross-sectional views showing anexample of a mechanism for making fine adjustment of the attachmentposition of the second optical component in the left and rightdirections.

FIG. 12 is a schematic plan diagram of the principal components of yetanother example of an optical system of the projection-type displayapparatus in accordance with the invention.

FIG. 13 is an explanatory diagram showing the operation of thereflectance-type liquid crystal device shown in FIG. 9.

FIG. 14 is a schematic drawing showing the optical system of a generalprojection-type display apparatus provided with an integrator opticalsystem.

FIG. 15 is an explanatory diagram showing the relationship between theillumination range on the liquid crystal light valves and the imageforming range.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The following is a description of a projection-type display apparatus towhich the invention has been applied, with reference to the drawings. Inthe following description, the three orthogonally intersectingdirections are represented by X, Y, and Z, with Z being the direction ofprogress of light.

FIG. 1 is a perspective view of a projection-type display apparatus inaccordance with the present embodiment of the invention. Theprojection-type display apparatus 1000 in accordance with the inventionis formed such that light fluxes of the colors red, blue, and green areextracted from the light emitted from a light source via an integratoroptical system and color separating system. Each of the colors are ledto liquid crystal light valves positioned corresponding with each colorand modulated according to color image signals. Followingre-synthesizing of the color fluxes of each color after modulation, thecolor fluxes are subjected to enlarged projection thereof on a screenvia a projecting lens.

As shown in FIG. 1, the projection-type display apparatus 1000 has arectangular outer casing 2, and the outer casing 2 basically includes anupper case 3, a lower case 4, and a front case 5 defining the front faceof the apparatus. The leading end potion of the projecting lens unit 6protrudes from the center of the front case 5.

FIG. 2 shows the positional relationship of the components within theouter casing 2 of the projection-type display apparatus 1000. As shownin the Figure, an electric power source unit 7 is disposed at the rearof the outer casing 2. A light source lamp unit 8 is disposed adjacentthe electric power source unit 7 toward the front of the apparatus.Also, an optical unit 9 is disposed adjacent the base end of theprojecting lens unit 6, which is disposed at the center front of theoptical unit 9.

An interface board 11 is disposed at one side of the optical unit 9. Theinterface board 11 is mounted with an input/output interface circuitfacing toward the front and rear sides of the apparatus. A video board12 mounted with a video signal processing circuit is parallel to theinterface board 11. A control board 13 is disposed above the lightsource lamp unit 8 and optical unit 9 for driving and controlling theapparatus. Speakers 14R and 14L are disposed at the front right and leftcorners of the apparatus thereof.

A suction fan 15A for cooling is disposed at the center of the upperside of the optical unit 9, and a circulating fan 15B for formingcooling circulation is disposed at the center of the bottom side of theoptical unit 9. Also, an exhaust fan 16 is positioned at the side of theapparatus adjacent to the rear side of the light source lamp unit 8. Anauxiliary cooling fan 17 for introducing cooling air flow from thesuction fan 15A into the electric power source unit 7 is positionedadjacent the edge of the boards 11 and 12 at the electrical power sourceunit 7.

Further, a floppy disk drive unit (FDD) 18 is disposed immediately abovethe electric power source unit 7 at the left side of the apparatus.

FIG. 3 is a broken away view of the optical unit 9 and projecting lensunit 6. As shown in the Figure, the optical unit 9 is of such astructure that the optical devices other than the prism unit 910 thatincludes the color synthesizing device are supported by the upper andlower light guides 901 and 902. The upper light guide 901 and lowerlight guide 902 are each fixed by fixing screws to the upper case 3 andlower case 4, respectively. Also, the upper light guide 901 and lowerlight guide 902 are also fixed to the side of the prism unit 910 byfixing screws in the same manner. The prism unit 910 is fixed by afixing screw to the rear side of a thick head plate 903 which is adie-cast plate The base side of the projecting lens unit 6 is fixed tothe front face of the head plate 903 by fixing screws in the same way.

FIG. 4 shows a schematic of the optical system which is assembled to theoptical unit 9. The optical system which is assembled to the opticalunit 9 is described with reference to this Figure. The optical systemaccording to the present embodiment includes a discharge lamp 81 whichis a component of the aforementioned light source lamp unit 8, and anintegrator optical system 923 which includes a first lens plate 921 anda second lens plate 922 which are uniform illumination optical devices.This system also includes a color separating optical system 924 whichseparates the white light flux W emitted from the integrator opticalsystem 923 into the red, green, and blue color light fluxes, i.e., R, G,and B, three liquid crystal light valves 925R, 925G, and 925B whichserve as light valves for modulating the color light fluxes, a prismunit 910 serving as a color synthesizing system for re-synthesizing themodulated color fluxes, and a projecting lens unit 6 for performingenlarged projection of the synthesized light flux on the surface of ascreen 100. Further, the system includes a light guiding system 927 forguiding the blue-colored light flux B of the color light fluxesseparated by the color separating optical system 924 to the liquidcrystal light valve 925B.

Lamps such as halogen lamps, metal-halide lamps, xenon lamps, and thelike can be used as the discharge lamp 81. The uniform illuminationoptical system 923 is provided with a reflecting mirror 931, so as tobend the center optical axis la of the emitted light from the integratoroptical system 923 toward the front of the apparatus. The first andsecond lens plates 921 and 922 are disposed on either side of thismirror 931 in an orthogonal relationship.

The light emitted from the discharge lamp 81 is reflected by thereflecting face 821 of the reflector 82 and is irradiated upon the firstlens plate 921 as parallel light beams, each beam being projected as asecondary light source image upon the incidence plate of each lens ofthe second lens plate 922 via the first lens plate 921, and the lightemitted from this second lens plate 922 illuminates the object to beilluminated. In other words, the image forming range of each light valve925R, 925G, and 925B is illuminated.

The color separating optical system 924 includes a blue-green reflectingdichroic mirror 941, a green reflecting dichroic mirror 942, and areflecting mirror 943. In the blue-green reflecting dichroic mirror 941,the blue light flux B and the green light flux G in the white light fluxW is reflected at a right angle, and go to the green reflecting dichroicmirror 942.

The red light flux R passes through the mirror 941, is reflected at aright angle by the posterior reflecting mirror 943, and is emitted fromthe red light flux emitting portion 944 to the prism unit 910. The blueand green light fluxes B and G are reflected by the mirror 941. Thegreen light flux G thereof is alone reflected at the green reflectingdichroic mirror 942, and is emitted from the green light flux emittingportion 945 to the prism unit 910. The blue light flux B passes throughthe mirror 942 and go to the light guiding system 927 via the blue lightflux emitting portion 946. In the present embodiment, the arrangement issuch that the distances between the white light flux emitting portion ofthe integrator optical system 923 to each of the light flux emittingportions 944, 945, and 946 of the color separating optical system 924are the same.

Focusing lenses 951 and 952 are respectively provided to each of the redlight flux and green light flux emitting portions 944 and 945 of thecolor separating optical system 924. Accordingly, the light flux of eachcolor emitted from each of the emitting portions becomes incident lightto the focusing lenses 951 and 952, and are made to be parallel.

The parallel red and green light fluxes R and G are cast into thecrystal light valves 925R and 925G, and modulated adding imageinformation corresponding to each color light. In other words, the lightvalves are subjected to switching control according to image informationby a driving device (not shown), and accordingly, each of the lightfluxes passing through is modulated. Conventional mechanisms can be usedas the driving device. On the other hand, the blue light flux B is ledto the corresponding crystal light valve 925B via the light guidingsystem 927, and similar modulation is performed in accordance with imageinformation. The light valves may be of the type using poly-silicone TFTas the switching devices, for example.

The light guiding system 927 includes a focusing lens 953, an incidentside reflecting mirror 971, an emitting side reflecting mirror 972, anintermediate lens 973 placed between these, and a focusing lens 954disposed before the liquid crystal panel 925B. The distance of theoptical path of each color light flux, i.e., the distance between thewhite light flux emitting portion of the integrator optical system toeach of the liquid crystal light valves 925R, 925G, and 925B is longestfor the blue light flux B, so that the amount of light lost is greatestfor the blue light flux. However, the amount of light lost for the bluelight flux can be reduced by introducing the light guiding system 927.

Next, the light fluxes of each color modulated by passing through theliquid crystal light valves 925R, 925G, and 925B of each color are castinto the color synthesizing optical system 910, and synthesized. In thepresent embodiment, a prism unit 910 that includes dichroic prisms asdescribed above is used as the color synthesizing optical system. Thecolor image re-synthesized is subjected to enlarged projection on thesurface of a screen 100 by a projecting lens unit 6. (Liquid crystallight valve illumination range adjusting mechanism)

Regarding the projection-type display apparatus 1 in accordance with thepresent embodiment, as shown in FIG. 4, the illumination range on theliquid crystal light valve 951 from the integrator optical system 923provides fine adjustment in the vertical (±Y direction) and horizontal(±X direction) directions as to the image forming range of the liquidcrystal light valve.

FIG. 5(A) shows the relationship between the illumination range B on theliquid crystal light valve 951 from the integrator optical system 923and the image formation range A of the liquid crystal light valve 925.Generally, the projecting range of the screen 100 is rectangular, so theimage formation range A of the liquid crystal light valve 951 iscorrespondingly rectangular. The illumination range B from the uniformillumination optical system 923, i.e., the range illustrated byimaginary lines in the Figure, is also correspondingly rectangular.

As described above, the image formation range A of the liquid crystallight valve 951 is sized to be distinctly smaller than the illuminationrange B. In other words, a margin of a certain width is provided aroundthe image formation range A. Providing for a margin enables the displayrange A to always be disposed within the illumination range B, even whenthe image formation position of the illumination range changes due to amargin of error in positioning the optical parts, such as each of thelens plates 921 and 922 of the integrator optical system 923.

In the present embodiment, as shown in the arrows in the Figure, thelens plates 921 and 922 are arranged so as to enable fine adjustment ofthe attachment position thereof in vertical and horizontal directionsfollowing a plate perpendicular to the optical axis 1 a, by a positionadjusting mechanism. A leaf spring and position adjusting screw can beused as the position adjusting mechanism.

FIGS. 6(A) and 6(B) are sectional views showing an example of amechanism for providing fine adjustment of the attachment position ofthe lens plate 921 in the left and right directions. FIG. 6(B) is across-sectional diagram following the line S—S in FIG. 6(A). As shown inthe diagrams, the position adjusting mechanism 700 is provided at theupper and lower light guides 901 and 902. A pair of right and left walls711 and 712 extending in the vertical direction following a platevertical to the optical axis 1 a, a base wall 713 connecting the loweredges of the vertical walls 711 and 712, and an upper wall 714connecting the upper edges of the vertical walls 711 and 712, are formedby the upper and lower light guides 901 and 902, with the lens plate 921being surrounded by the walls 711-714. The bottom end of the lens plate921 is inserted into a holding groove 715 which is formed in the basewall 713. Also, the lower portion of the lens plate 921 is pressedtoward the upstream direction of the optical path (−Z direction) by afixed spring 717 which is mounted by a screw 716 to the base wall 713.The upper portion of the lens plate 921 is pressed in the same directionby a fixed spring 719 which is mounted by a screw 718 to the upper wall714. The upper portion of the lens plate 921 contacts a protrudingportion 710 which is provided at the upper wall 714. Accordingly, thelens plate 921 is supported by one of the vertical walls 711 via analignment spring 720. Also, the lens plate 921 is pressed toward one ofthe vertical walls 711 by an adjusting screw 721 which is provided atthe other vertical wall 712. Thus, the attachment position of the lensplate 921 can be moved only in the left and right directions (±Xdirection) by adjusting the adjusting screw 721.

As shown in FIG. 5(B), in cases wherein the illumination range B isoffset in the horizontal direction as to the image formation range A ofthe liquid crystal light valve 925, and part of the image formationrange A is not illuminated, the adjusting screw 721 can be tightened orloosened to provide fine adjustment of the attachment position of thelens plate 921 in the left and right direction, thus shifting theposition of the illumination range B sideways, and as shown in FIG.5(C), the illumination range B is made to encompass the image formationrange A.

Also, with the present embodiment, an alignment spring 720 that includesa generally L-shaped leaf spring is used. The adjusting screw 721presses the approximate center portion of the side of the lens plate 921on the side of the vertical wall 712. Accordingly, uniform movement ofthe lens plate 921 can be realized with few parts.

On the other hand, a mechanism for providing fine adjustment of theattachment position of the lens plate 922 in the vertical directions (±Ydirection), does not have to include the adjustment screw 721 andalignment spring 720 provided at the vertical walls 711 and 712 as shownin FIGS. 6(A) and 6(B). Instead, an adjustment screw and alignmentspring can be provided at the upper wall 714 and lower wall 713, thesame as described above to facilitate easy adjustment. Accordingly,detailed description thereof will be omitted.

Also, according to the present embodiment, subsequent to fine adjustmentof the lens plates 921 and 922, adhesive agent is injected via adhesiveagent injection holes 904 a, 904 b, 905 a, and 905 b shown in FIG. 3,provided in the upper light guide 901, thus fixing the lens plates 921and 922. Such fixing is not necessarily required, but is advantageous asit can ensure the prevention of shifting of the attachment position ofthe lens plates 921 and 922 due to external shock.

Also, as for a position adjusting mechanism using an adjustment screwand alignment spring, an arrangement can be used wherein an adjustmentscrew and alignment spring are not provided directly to the upper andlower light guides 901 and 902, and instead a separate lens holder isused.

Further, the fine adjustment in the left and right directions (±Xdirection) can be made either automatically or manually, by measuringthe illuminance on the area of the image formation range A on the liquidcrystal light valve 925G. In the structure shown in FIG. 5(B), theillumination region B is shifted to the left, and the illuminance of theimage formation range A on the right side of the liquid crystal lightvalve 925G is low. In order to adjust such offset of the illuminationrange B, the attachment position of the lens plate 921 should be shiftedto the left or right (±X direction) until the right and left illuminanceP1 and P2 of the image formation range A are of a constant value.However, this adjusting method requires that a constant value be setbeforehand, which creates difficulty in dealing with a situation wherethe light source has been changed to such with low luminosity.

Since there is no need to set a constant value beforehand if theattachment position of the lens plate 921 is shifted to the left orright until the right and left illuminance P1 and P2 of the imageformation range A are of an equal value, a situation where the lightsource has been changed to such with low luminosity can be dealt witheasily. Also, since there is no need to set a constant value beforehandeven if the attachment position of the lens plate 921 is shifted to theleft or right until the sum of the right and left illuminance P1 and P2of the image formation range A is maximal, a situation where the lightsource has been changed to such with low luminosity can be dealt witheasily.

Instead of using the method wherein the illuminance in the area of theimage formation range A on the liquid crystal light valve 925G ismeasured, the fine adjustment in the left and right directions (±Xdirection) can be performed automatically or manually, by setting theliquid crystal light valve 925G to transmit illumination light, andmeasuring the illuminance of the area around the projected image whenthe image is projected on the screen 100.

When projection is made to the screen 100 in the structure shown in FIG.5(B), the projected image B is not projected to the left edge of therange A′ to which the image should be projected, as shown in FIG. 5(D).Accordingly, illuminance of the left edge becomes low. Thus, theilluminance Q1 and Q2 of the left and right portions of the range A′ towhich the image should be projected is measured, and fine adjustment canbe made by a method similar to the aforementioned method whereinilluminance measurement is made on the liquid crystal light valve 925G.For example, the attachment position of the lens plate 921 is shifted tothe left and right until the value of the illuminance Q1 and Q2 becomesconstant, or the attachment position of the lens plate 921 is shifted tothe left and right until the value of the illuminance Q1 and Q2 becomesequal, or further, the attachment position of the lens plate 921 isshifted to the left and right until the sum value of the illuminance Q1and Q2 becomes maximal. Also, as described above, situations where thelight source has been changed to such with low luminosity can be dealtwith easily by shifting the attachment position of the lens plate 921 tothe left and right until the value of the illuminance Q1 and Q2 becomesequal or until the sum value of the illuminance Q1 and Q2 becomesmaximal.

Fine adjustment in the up and down directions (±Y direction) can beperformed automatically or manually, by measuring the illuminance at theupper and lower portions of the image forming range A, or theilluminance at the upper and lower portions of the projected image. Inthe case of vertical adjustment, the attachment position of the lensplate 922 should be shifted in the vertical direction until theilluminance of two spots become a constant value, the same as withhorizontal fine adjustment. Also, situations where the light source hasbeen changed to such with low luminosity can be dealt with easily byshifting the attachment position of the lens plate 922 up and down untilthe illuminance of the two spots becomes equal or until the sum value ofthe two spots becomes maximal.

Further, fine adjustment of the integrator optical system 923 may beperformed using the other liquid crystal light valves 925R or 925Binstead of the liquid crystal light valve 925G.

When performing fine adjustment, the first lens plate 921 and the secondlens plate 922 may be moved simultaneously, but a sequential attachmentposition fine adjustment method may be used. For example, the first lensplate 921 is first moved in the left and right directions to performfine adjustment in the horizontal direction, and then the second lensplate 922 is second moved in the up and down directions to perform fineadjustment in the vertical direction. Of course, similar adjustment canbe made wherein fine adjustment is made in the vertical direction,following fine adjustment in the horizontal direction.

While in the above example, the first lens plate 921 is first moved inthe left and right directions to perform fine adjustment, and the secondlens plate 922 in the up and down directions, but these directions maybe reversed. Further, the only one of the first and second lens plates921 and 922 can be made to be subjected to fine adjustment. Further, theattachment position of the first and second lens plates 921 and 922 maybe made to be adjustable in any direction intersecting the optical axis.By enabling such adjustment in arbitrary directions, warping on theillumination range B shown in FIG. 7 can also be prevented, thusfacilitating improved uniformity of illumination. The following fourcombinations are examples of adjustment forms of these.

Direction of Adjustment First integrator lens Second integrator lens (1)Horizontal Vertical (2) Vertical Horizontal (3) Fixed (non-adjustable)Vertical, Horizontal, or arbitrary (4) Vertical, Horizontal, Fixed(non-adjustable) or arbitrary

Thus, enabling fine adjustment of the attachment position of theintegrator optical system obviates the need to provide a certain marginaround the image formation area A of the liquid crystal light valvewherein shifting of the illumination range is taken into considerationbeforehand, as with the conventional art. Accordingly, the margin to beprovided around the image formation area A can be extremely small, thusproviding increased effectiveness of the usage of illumination light andconsequently increasing the brightness of the projected image.

In other words, even if the margin is reduced, the problem of a portionof the image formation area A extending beyond the illumination range B,as shown in FIG. 5(B), can be obviated by making fine adjustment of theattachment position of the lens plates 921 and 922. Hence, the inventionprevents problems such as shadows forming on the edge of the projectedimage.

Further, another reason that the illumination range B of the integratoroptical system 923 shifts from the image formation area A of the liquidcrystal light valve is due to the margin of error of the attachmentangle of the reflecting surface of the reflecting mirrors disposed inthe optical path of the light fluxes of each color. The attachment angleof the reflecting surface of the reflecting mirror relative to theoptical axis is 45°, but when this angle is shifted, a portion of theimage formation area A may shift out of the illumination range B, asshown in FIG. 5(B). Further, as shown in FIGS. 7(A) and 7(B), this canresult in warping of the illumination range B, causing non-uniformity inthe illuminance of the left side of the illumination range B and theilluminance of the right side thereof, thus destroying the advantages ofusing the integrator optical system 923.

Particularly, with the projection-type display apparatus 1000 inaccordance with the present embodiment, fine adjustment of theintegrator optical system 923 is performed with the liquid crystal lightvalve 925G as a standard reference. However, if the attachment angles ofthe reflecting surfaces of the mirrors 943, 972, and 971 shown in FIG. 4are not 45° relative to the optical axis, the illumination ranges ofeach will be offset as to the image forming area of the liquid crystallight valves 925R and 925B. Also, if the focusing lens 953 and theintermediate lens 973 are not attached to the predetermined attachmentpositions, the illumination range will be offset as to the image formingarea of the liquid crystal light valve 925B.

Now, with the projection-type display apparatus 1000 in accordance withthe present embodiment, in addition to the aforementioned fineadjustment of the integrator optical system 923, the angle of thereflecting surface of the mirror 943 which reflects the red light flux Rtoward the liquid crystal light valve 925R and the mirror 972 whichreflects the blue light flux B toward the liquid crystal light valve925B, as shown in FIG. 4, can be subjected to fine adjustment as to theincident optical axis around an axial line (following the arrows in FIG.4) vertical to a plane including the incident optical axis and reflectedoptical axis. An angle adjusting mechanism for this reflecting mirrorattachment angle can include a leaf spring and angle adjusting screwsimilar to that of the above described position adjusting mechanism forthe integrator optical system 923.

FIGS. 8(A)-(C) show a mechanism for performing fine adjustment of theattachment angle of the reflecting mirror 972. FIG. 8(A) shows theholder plate 740 which holds the reflecting mirror 972. FIG. 8(B) showsthe mechanism for performing fine adjustment of the attachment angle ofthe reflecting mirror 972 from the side of the upper light guide 901.FIG. 8(C) shows the mechanism for performing fine adjustment of theattachment angle of the reflecting mirror 972 from the T—Tcross-sectional portion in FIG. 8(B).

As shown in these diagrams, the angle adjustment mechanism 730 has aholder plate 740, and the lower portion of the reflecting mirror 972 isheld from the side thereof opposite to the side of the reflectingsurface, by the holding members 746 a and 746 b provided at this holderplate 740. Also, the upper portion of the reflecting mirror 972 is fixedto the holder plate 740 by a clip 748. An axial portion 741 extendsvertically and is formed at the central portion of the surface of thisholder plate 740. This axial portion 741 is rotatably supported by thelower light guide 902. Accordingly, the reflecting mirror 972 can berotated around the axial line 1 b of the axial portion 741 via theholder plate 740, by only a predetermined amount. Also, a spring holder744 is provided at the other side portion of the holder plate 740, andthe first fulcrum 742 a of the alignment spring 742 is inserted intothis spring holder 744. The fulcrums 742 b and 742 c of the alignmentspring 742 contact a supporting portion 749 provided at the lower lightguide 902. Accordingly, the holder plate 740 is supported at the lowerlight guide 902 via the alignment spring 742. Further, the spring holder744 of the holder plate 740 is pressed in the direction of arrow G inthe Figure by an adjusting screw 743 provided at a plate 770 fixed tothe lower light guide 902 by a screw 771.

Accordingly, inserting a jig from the screw operating portion 902 aprovided at the lower light guide 902 and increasing the amount ofscrewing of the adjusting screw 743 causes the side portion of theholder plate 740 to be pressed toward the direction G by the adjustingscrew 743, so that the holder plate 740 circles around the axial line 1b of the axial portion 741 shown by arrow R1 in FIG. 8(B). Thus, theangle of the reflecting surface of the reflecting mirror 972 can bechanged so that the incident angle of the incident light to thereflecting mirror 972 is increased.

Conversely, reducing the amount of screwing of the adjusting screw 743causes the side portion or the holder plate 740 to be pulled toward thedirection -G by the alignment spring 742, so that the holder plate 740circles around the axial line 1 b of the axial portion 741 shown byarrow R2 in FIG. 8(B). Thus, the angle of the reflecting surface of thereflecting mirror 972 can be changed so that the incident angle of theincident light to the reflecting mirror 972 is decreased. In otherwords, by adjusting the screwing amount of the adjusting screw 743, theangle of the reflecting surface of the reflecting mirror 972 can beadjusted around an axial line vertical to a plane including the incidentoptical axis and reflected optical axis. Incidentally, the mechanism foradjusting the angle of the reflecting surface of the other reflectingmirrors can use a mechanism the same as that described above.

Also, in accordance with the present embodiment, subsequent to fineadjustment of the attachment angle of the reflecting mirrors 943 and972, adhesive agent is injected from adhesive agent injection holes 906a, 906 b, 907 a, and 907 b (shown in FIG. 3) provided in the upper lightguide 901, thus fixing the reflecting mirrors 943 and 972. Such fixingis not necessarily required, but is advantageous as it can ensure theprevention of shifting of the reflecting mirrors 943 and 972 due toexternal shock.

Further, this fine adjustment can be performed automatically ormanually, by measuring the illuminance around the image forming range,on the liquid crystal light valve 925R or liquid crystal light valve925B. As with the above-described fine adjustment of the lens plates,the attachment angle of each of the reflecting mirrors 943 and 972should be shifted until the left and right illuminance P1 and P2 of theimage formation range A are of a constant value. Also, situations wherethe light source has been changed to such with low luminosity can bedealt with by shifting the attachment angle of each of the reflectingmirrors 943 and 972 until the left and right illuminance P1 and P2 ofthe image formation range A are equal, or by shifting the attachmentangle of the reflecting mirrors 943 and 972 until the sum of the leftand right illuminance P1 and P2 of the image formation range A becomesmaximal.

Now, regarding fine adjustment of each of the reflecting mirrors 943 and972, as with the fine adjustment of the lens plates, instead of usingthe method wherein the illuminance in the area of the image formationrange A on the liquid crystal light valve 925R or liquid crystal lightvalve 925B is measured, the fine adjustment can be performedautomatically or manually, by setting the liquid crystal light valve925R or liquid crystal light valve 925B to transmit illumination light,and measuring the illuminance of the area around the projected imagewhen the image is projected on the screen 100. In other words, whenprojection is made to the screen 100 as shown in FIGS. 7(A) and 7(B),the illuminance of the left and right sides becomes non-uniform. To dealwith this, the illuminance of the left and right sides of projectedimage is measured, and fine adjustment is made in the same manner aswith the illumination measurement of the image forming range A, and theattachment angle of the reflecting mirrors 943 and 972 is shifted untilthe value of the left and right illuminance become constant, or the leftand right illuminance become equal, the sum value of the left and rightilluminance becomes maximal.

When performing fine adjustment, the reflecting mirrors 943 and 972 maybe moved simultaneously. However, a sequential attachment angleadjustment method may be used wherein the reflecting mirror 943 is firstmoved to perform fine adjustment based on the projected image or imageforming range from the liquid crystal light valve 925R, and then thereflecting mirror 972 is moved to perform fine angle adjustment based onthe projected image or image forming range from the liquid crystal lightvalve 925B.

While in accordance with present embodiment, the attachment angle of thereflecting mirrors 943 and 972 closest to the liquid crystal lightvalves 925R and 925B can be adjusted, part or all of the other opticalcomponents, such as the blue reflecting dichroic mirror 941, greenreflecting dichroic mirror 942, or the incident side reflecting mirror971 may be subjected to fine adjustment of the attachment anglesthereof. Also, the position of the intermediate lens 973 or focusinglens 953 may be subjected to adjustment instead of the reflecting mirror972. However, the arrangement in accordance with the present embodiment,subjecting the attachment angle of the reflecting mirrors 943 and 972closest to the liquid crystal light valves 925R and 925B to fineadjusting is most advantageous, from the perspective of apparatusconstruction and from the perspective of precision of angle adjustment.

Thus, providing fine adjustment of the attachment angle of thereflecting mirrors 943 and 972 obviates the need to provide a widemargin around the image formation area A of the liquid crystal lightvalve wherein shifting of the illumination range is taken intoconsideration beforehand, as with conventional art. Accordingly, themargin to be provided around the image formation area A can be extremelysmall, thus providing increased effectiveness of the usage ofillumination light and consequently increasing the brightness of theprojected image.

Also, even if the margin is reduced, the problem of a portion of theimage formation area A extending beyond the illumination range B asshown in FIGS. 7(A) and 7(B) can be obviated by providing fineadjustment of the attachment angle of the reflecting mirrors 943 and972. Hence, the invention prevents problems such as shadows forming onthe edge of the projected image.

Further, by providing fine adjustment of the attachment angle of thereflecting mirrors 943 and 972, warping of the illumination range B canbe eliminated, thus optimizing the merits of enabling uniformillumination with the integrator optical system 923, which facilitatesobtaining of a projected image which is extremely uniform in brightness.

Also, such an angle adjusting mechanism for optical components such asreflecting mirrors is effective in projection-type display apparatuseswhich do not use an integrator optical system 923.

The following is a description of another structure of a projection-typedisplay apparatus to which the invention has been applied. The opticalsystem of the projection-type display apparatus 2000 in accordance withthe invention includes a structure enabling a polarization illuminationwhich includes an integrator optical system and a polarization beamsplitter of a special form. In the present embodiment, the componentswhich are the same as those in the above-described projection-typedisplay apparatus 1000 are provided with the same reference numerals asthose given in FIGS. 1-8, and detailed description thereof is omitted.

FIG. 9 shows the principal components of the optical system of theprojection-type display apparatus 2000 in accordance with the invention,illustrating the construction on an X-Z plane. The projection-typedisplay apparatus 2000 in accordance with the invention generallyincludes a polarization illumination device 1, a color splitting devicefor splitting the white light flux into three colors, threetransmittance-type liquid crystal devices for modulating the light ofeach color according to display information and forming a display image,a color synthesizing device for synthesizing the color light of thethree colors and forming a color image, and a projecting optical systemfor projection display of the color image.

The polarization illumination device 1 includes a light source portion10 for emitting random polarization light fluxes in a single direction.The random polarization light fluxes emitted from this light sourceportion 10 are converted into a polarization light flux of almost onetype, by a polarization converting device 20.

The light source portion 10 generally includes a light source lamp 101and a parabolic surface reflector 102. The light emitted from the lightsource lamp is reflected in one direction by the parabolic surfacereflector 102, and is cast into the polarization converting device 20 asparallel light flux. Light source portion 10 is disposed so that thelight source optical axis R of the light source portion 10 is shifted asto the system optical axis L in a parallel manner in the X direction bya constant distance of D.

The polarization converting device 20 includes a first optical component200 and a second optical component 300.

The first optical component 200 is equivalent to the first lens plate921 in the above-described projection-type display apparatus 1000, withthe cross section on the X-Y plane including a matrix-like array of aplurality of rectangular light flux splitting lenses 201. The lightsource optical axis R is disposed so as to intersect the center of thefirst optical component 200. The light cast into the first opticalcomponent 200 is split into a plurality of intermediate light fluxes 202by the light flux splitting lenses 201. At the same time, a number offocused images equal to the number of light flux splitting lenses areformed at a position at which the intermediate light fluxes areconverged within a plane perpendicular to the system optical axis L (theX-Y plane shown in FIG. 9) by focusing effects of the light fluxsplitting lenses. Also, the cross-section of the light flux splittinglenses 201 on the X-Y plane is set so as to be analogous to the form ofthe image forming range of the liquid crystal light valves. In thepresent embodiment, the cross-section of the light flux splitting lenses201 on the X-Y plane is set to be rectangular, since an image formingrange is rectangular and long in the X direction on the X-Y plane.

The second optical component 300 is a complex member that generallyincludes a focusing lens array 310, a polarization splitting unit array320, a selective phase difference plate 380, and a combining lens 390,being positioned near the position at which the focused image from thefirst optical component 200 is formed, within a plane perpendicular tothe system light axis L (the X-Y plane shown in FIG. 9). Also, if thelight flux being cast into the first optical component 200 has extremelygood parallelism, the focusing lens array 310 can be omitted from thesecond optical component. This second optical component 300 canspatially split each of the intermediate light fluxes 202 intoP-polarization light flux and S-polarization light flux, and then emitthe P-polarization light flux and S-polarization light flux with thepolarization direction of one matching the polarization direction of theother, and leading the light fluxes almost matched in direction to asingle illumination range.

The focusing lens array 310 includes almost the same structure as thatof the first optical component 200. For example, the focusing lens array310 is a matrix array of focusing lenses 311 equal in number to thelight flux splitting lenses 201 of the first optical component 200,which focus each of the intermediate light fluxes to a particular spoton the polarization splitting unit array 320. Accordingly, it isdesirable that-the lens properties of each of the focusing lenses beoptimized, in accordance with the properties of the intermediate lightfluxes 202 formed by the first optical component 200, and wherein it isideal that the inclination of the main ray of the light incident to thepolarization splitting unit array 320 be parallel to the system opticalaxis L. However, because of considerations of lowering costs of theoptical system and of ease of design, an object exactly identical to thefirst optical component 200 can be used for the focusing lens array 310,or a focusing lens array that includes focusing lenses analogous to theform of the light flux splitting lenses 201 on the X-Y plane can be usedas the focusing lens array. Thus, in accordance with the presentembodiment, first optical component 200 is used for the focusing lensarray 310. Further, the focusing lens array 310 may be separated fromthe polarization splitting unit array 320, i.e., to the side closer tothe first optical component 200.

As shown in FIGS. 10 (A) and 10(B), the polarization splitting unitarray 320 includes a plurality of polarization splitting units 330arrayed on a matrix form. The arraying of the polarization splittingunits 330 corresponds with the lens properties of the light fluxsplitting lenses 201 of the first optical component 200, and thearraying thereof. In accordance with the present embodiment, concentriclight flux splitting lenses 201 which have all of the same lensproperties are used. These light flux splitting lenses are arrayed in anorthogonal matrix form to form the first optical component 200. Thus,the polarization splitting unit array 320 includes polarizationsplitting units 330 arrayed in an orthogonal matrix form, all in thesame direction. If the polarization splitting units arrayed in the Ydirection are all identical polarization splitting units, it isadvantageous to use a polarization splitting unit array 320 thatincludes polarization splitting units which are long and thin in the Ydirection and arrayed on the X direction, from the perspective ofreducing light lost at the surface between the polarization splittingunits, and also from the perspective of facilitating manufacturing costsof the polarization splitting unit array.

The polarization splitting units 330 are integral having a pair ofpolarization light splitting surface 331 and reflecting surface 332within, and spatially split each of the intermediate light fluxes castinto the polarization splitting unit into P-polarization light flux andS-polarization light flux. The cross-section form of the polarizationlight splitting units 330 on the X-Y plane is analogous with thecross-section form of the light flux splitting lenses 201 on the X-Yplane, i.e., a rectangular form which is long in the width direction.Accordingly, the polarization light splitting surface 331 and reflectingsurface 332 are lined up in the sideways direction (X direction). Here,the polarization light splitting surface 331 and reflecting surface 332are disposed such that the polarization light splitting surface 331 isat an inclination of approximately 45° to the system optical axis L, thereflecting surface 332 is parallel with the polarization splittingsurface, and further, the area of the polarization light splittingsurface 331 being projected upon the X-Y plane (equal to the area of thelater-described P emission plane 333) is equal to the reflecting surface332 being projected upon the X-Y plane (equal to the area of thelater-described S emission plane 334).

Accordingly, in accordance with the present embodiment, the width Wpupon the X-Y plane of the range at which the polarization lightsplitting surface 331 extends and the width Wm upon the X-Y plane of therange at which the reflecting surface 332 extends are equal. Also,generally, the polarization light splitting surface 331 can be formed ofa dielectric multi-layer film, and the reflecting surface 332 can beformed of a dielectric multi-layer film or aluminum film.

Incident light to the polarization splitting units 330 is split at thepolarization light splitting surface 331 into P polarization light flux335 which passes through the polarization light splitting surface 331without changing direction and S polarization light flux 336 which isreflected at the polarization light splitting surface 331 and changesdirection toward the reflecting surface 332. The P polarization lightflux 335 is emitted from the polarization light splitting units withoutchange via the P emission plane 333, and the S polarization light flux336 changes direction again at the reflecting surface 332. The Spolarization light flux 336 is parallel with the P polarization lightflux 335, and is emitted from the polarization splitting units via the Semission plane 334. Accordingly, the random polarization light flux castinto the polarization splitting unit 330 is split into two types ofpolarization light fluxes, the P polarization light flux 335 and Spolarization light flux 336. The P and S polarization light fluxes 335and 336 have different polarization directions, and are emitted fromdifferent positions on the polarization splitting units (P emissionplane 333 and S emission plane 334) toward the same general direction.

Since the polarization splitting units operate as described above, it isnecessary to guide each of the intermediate light fluxes 202 to therange where the polarization light splitting surface 331 extends withinthe polarization splitting units 330. To this end, the positionalrelationship of each of the focusing lenses 311 of each of thepolarization light splitting surface 331 and the lens properties of eachof the focusing lenses 311 are set so that the intermediate light fluxesare cast to the center portion of the polarization light splittingsurface within the polarization splitting units. Particularly, inaccordance with the present embodiment, the focusing lens array 310 isshifted in the X direction as to the polarization splitting unit array320 by a distance corresponding to ¼ of the width W of the polarizationsplitting units, so that the center axis of each of the focusing lensesis positioned at the center portion of the polarization light splittingsurface 331 within the polarization splitting units 330.

Again, description is made with reference to FIG. 9. A selective phasedifference plate 380 that includes methodically arrayed ½ phasedifference plates is disposed on the emitting side of the polarizationlight splitting unit array 320. For example, ½ phase difference platesare arrayed only at the portion of the P emission plane 333 of thepolarization splitting units 330 of the polarization splitting unitarray 320, and ½ phase difference plates are not provided at the Semission plane 334 portion. Because of the position of the ½ phasedifference plates, the P polarization light fluxes emitted from thepolarization splitting units 330 receive the rotational effects of thepolarization direction when passing through the ½ phase differenceplates and are converted into S polarization light fluxes. On the otherhand, since the S polarization light fluxes emitted from the S emissionplane 334 portion do not pass through the ½ phase difference plates,there is no change in polarization direction, and pass through theselective phase difference plate 380 unchanged, as S polarization lightfluxes. In other words, due to the polarization splitting unit array 320and selective phase difference plate 380, the intermediate light fluxesof random polarization direction are converted into a type ofpolarization light flux (in this case, S polarization light flux).

A combining lens 390 is disposed at the emitting side of the selectivephase difference plate 380, and the light flux arranged to be Spolarization light flux by the selective phase difference plate 380 isled to the illumination range of each liquid crystal device by combininglens 390, and is superimposed on the illumination range. This combininglens 390 is equivalent to the second lens plate 922 in theabove-described projection-type display apparatus 1000. The combininglens 390 does not have to be a single lens member, and instead can be acollection of a plurality of lenses, as with the first optical component200 of the second lens plate 922 in the projection-type displayapparatus 1000.

Stating the functions of the second optical component 300 concisely, theintermediate light fluxes 202 split by the first optical component 200,i.e., the image plane cut out by the light flux splitting lenses 201,are superimposed on the illumination range by the second opticalcomponent 300. At the same time, the random intermediate light fluxesare spatially split by the encountered polarization splitting unit array320, and converted into polarization light flux of almost one type uponpassing through the selective phase difference plate 380. Accordingly,the image forming range of the liquid crystal light valve is illuminatedalmost uniformly by polarization light flux of almost one type.

As described above, the polarization illumination device 1 in accordancewith the invention is advantageous in that the random intermediate lightfluxes emitted from the light source portion 10 are converted intopolarization light flux of almost one type by the polarizationconverting device 20 that includes a first optical component 200 and asecond optical component 300. Thus, the image forming range of theliquid crystal light valve is illuminated almost uniformly by the lightflux with matched polarization direction. Also, almost all of the lightemitted from the light source portion can be introduced to the imageforming range of the liquid crystal light valves since there is verylittle light loss in the process of generating polarization light flux.Accordingly, the invention provides the advantage of extremely highlight usage efficiency.

Also, in accordance with the present embodiment, the focusing lens array310, polarization splitting unit array 320, selective phase differenceplate 380, and combining lens 390, of the second optical component 300are optically integrated, which further lessens light loss at thesurfaces thereof and increases light usage efficiency even more.

Further, matching the form of the image forming range which is arectangular and long in the width direction, the light flux splittinglenses 201 of the first optical component 200 are rectangular and longin the width direction, and at the same time, of a form which splits thetwo types of polarization light fluxes emitted from the polarizationsplitting unit array 320 in the sideways direction (X direction). Thus,even in the event of illuminating an image forming range which isrectangular and long in the width direction, no light is wasted, and theillumination efficiency (light usage efficiency) is increased.

Generally, if light flux with random polarization direction is simplysplit into P-polarization light flux and S-polarization light flux, theoverall width of the light flux subsequent to splitting is increasedtwofold, and the optical system accordingly becomes large. However, inaccordance with the polarization illumination device 1 of the invention,a plurality of fine focused images are formed by the first opticalcomponent 200, and the space without light generated in the formingprocesses is optimally used for placing the reflecting surface 332 ofpolarization splitting units 330 in that space, thus absorbing thesideways spreading of the light flux due to splitting into the twopolarization light fluxes, so that the width of the overall light fluxdoes not spread, consequently providing the advantage that a smalloptical system can be realized.

According to the projection-type display apparatus 2000 thus using thepolarization illumination device 1, a type of liquid crystal device isused which modulates one type of polarization light flux. Accordingly,if a conventional illumination device is used and random polarizationlight flux is introduced to the liquid crystal device, approximatelyhalf of the light of the random polarization light flux is absorbed bythe polarization plate (not shown) and is changed into heat, resultingin problems such as poor efficiency of light usage. Also, a large andnoisy cooling device is necessary to suppress the heat generated by thepolarization plate. However, these problems have been improved greatlyby the projection-type display apparatus 2000 in accordance with theinvention.

In the polarization illumination device 1 of the projection-type displayapparatus 2000 in accordance with the invention, rotation effect of thepolarization surface by the ½ phase difference plate is provided to oneof the polarization light fluxes, e.g., to only the P-polarization lightflux, thus aligning this light flux with the other polarization lightflux, e.g., the S-polarization light flux. Consequently, polarizationlight flux of almost one type with aligned polarization direction isintroduced to the three liquid crystal light valves 925R, 925G, and925B, the polarization plate absorbs very little light, and accordingly,efficiency of the light usage is improved and a bright projected imageis obtained.

Further, in the second optical component 300, the polarizationillumination device 1 spatially splits two types of polarization lightflux in the sideways direction (X direction). Accordingly, light is notwasted, and the arrangement is advantageous for illuminating the liquidcrystal devices that are rectangular and long in the width direction

Further, with the polarization illumination device 1 in accordance withthe present embodiment, spreading of the width of the light flux emittedby the polarization splitting unit array 320 is suppressed, even thougha polarization conversion optical component is incorporated into thestructure. This indicates that there is practically no light incident tothe liquid crystal devices having a great angle, upon illumination ofthe liquid crystal devices. Accordingly, a bright projection image canbe produced even without using an extremely wide-diameter projectionlens with a small f-stop number. As a result, a projection-type displayapparatus that is small in size can be provided.

In accordance with the projection-type display apparatus 2000 of thepresent embodiment having the above-described structure, placing atleast one of the first optical component 200 and second opticalcomponent 300 contained in the polarization illumination device 1 sothat the position thereof is adjustable in the direction orthogonallyintersecting the light axis L, enables fine adjustment of theillumination range of each of the liquid crystal light valves 925R,925G, and 925B toward the front, rear, left, and right directions, thusfacilitating positioning of the image forming range of each liquidcrystal device within the illumination range at all times.

An example of a mechanism whereby the attachment position of the secondoptical component 300 is subjected to fine adjustment in the verticaldirection (±Y direction) is described below. FIGS. 11(A) and 11(B) aresectional views showing a mechanism for providing fine adjustment of theattachment position thereof in the vertical direction. FIG. 11(B) is across-sectional view following line V—V in FIG. 11(A).

As shown in the diagrams, the position adjusting mechanism 750 isprovided above and below. A pair of right and left vertical walls 761and 762 that extend in the vertical direction and follow a platevertical to the optical axis 1 a, a base wall 763 connecting the loweredges of the vertical walls 761 and 762, and an upper wall 764connecting the upper edges of the vertical walls 761 and 762, are formedby the upper and lower light guides 901 and 902, with the second opticalcomponent 300 being surrounded by the walls 761-764. The second opticalcomponent 300 is pressed against the other vertical wall 762 by a fixingspring 769 mounted between the one vertical wall 761, which defines theleft and right (±X direction) attachment position. The bottom end of thesecond optical component 300 is inserted into a holding groove 768 whichis formed in the base wall 763. Also, the lower portion of the secondoptical component 300 is pressed toward the upstream direction of theoptical path (−Z direction) by a fixed spring 783 mounted by a screw 781to the base wall 713. The upper portion of the second optical component300 is pressed in the same direction by a fixed spring 782 mounted by ascrew 780 to the upper wall 764. Further, the upper portion of thesecond optical component 300 contacts a protruding portion 767 providedat the upper wall 764. The Z direction of the attachment position of thesecond optical component 300 is thereby defined.

On the other hand, the second optical component 300 is supported by thebase wall 763 via an alignment spring 765, and is pressed downwards (+Ydirection) by an adjusting screw 766 provided at the upper wall 764.Thus, the second optical component 300 can be moved in the up and downdirections (±Y direction) by adjusting the adjusting screw 766.Accordingly, in the event that the illumination region B shiftslengthwise as to the image forming range A of the liquid crystal lightvalve 925, and that part of the image forming range A is notilluminated, the adjustment screw 766 can be tightened or loosened thusproviding fine adjustment in the vertical direction of the attachmentposition of the second optical component 300. The illumination region Bis thereby shifted lengthwise and the illumination region B is disposedwithin the image forming range A.

Subsequently, adhesive agent is injected from adhesive agent injectionholes 908 a and 908 b provided in the upper light guide 901, to fix thesecond optical component 300. Such fixing is not necessarily required,but is advantageous since it can ensure the prevention of the attachmentposition of the second optical component 300 from shifting due toexternal shock.

Also, a mechanism for providing fine adjustment of the attachmentposition of the first optical component 200 and second optical component300 in the left and right directions (±X direction), can include aposition adjusting mechanism provided with an adjusting screws andalignment spring, as shown in FIG. 6.

Also, regarding a position adjusting mechanism using an adjustment screwand alignment spring, an adjustment screw and alignment spring do nothave to be provided directly to the upper and lower light guides 901 and902, and instead a separate lens holder can be used.

Further, in the present embodiment, the position adjusting mechanism ofeach of the above-described optical devices, the adjustment methodthereof, and the effects obtained by adjusting the illumination rangeare the same as those of the above-described projection-type displayapparatus 1000.

Thus, in accordance with the projection-type display apparatus 2000 ofthe present embodiment, providing fine adjustment of the attachmentposition of the first optical component 200 and second optical component300 obviates the need to provide a wide margin around the imageformation area of the liquid crystal devices, as with conventional art,taking shifting of the illumination range into consideration.Accordingly, the margin to be provided around the image formation areacan be extremely small, thus increasing the effectiveness of theillumination light usage and consequently increasing the brightness ofthe projected image.

Also, even if the margin is reduced, the problem of a portion of theimage formation area of the liquid crystal device extending beyond theillumination range of the polarization illumination device can beobviated, by providing fine adjustment of the attachment angle of eachof the above optical components. Hence, the invention prevents problemssuch as shadows forming on the edge of the projected image.

Also, in accordance with the present embodiment, the focusing lens array310, polarization splitting unit 320, selective phase difference plate380, and combining lens 390, of the second optical component 300 areoptically integrated, which lessens light loss occurring at the surfacesthereof, but these devices do not necessarily have to be integrated. Inthe event that these devices are not integrated, simply adjusting theposition of the focusing lens 310 enables the formation position of theillumination range to be adjusted.

In accordance with the projection-type display apparatus 2000 of thepresent embodiment, the illumination range of the liquid crystal deviceof the polarization illumination device 1 shifts relative to the imageforming range of the liquid crystal device because of the margin oferror of the attachment angle of the reflecting surface of thereflecting mirrors placed in the optical paths of the light fluxes ofeach color. The attachment angle of the reflecting surface of thereflecting mirror to the optical axis is 45°, but when this angle isshifted, a portion of the image formation area can shift out of theillumination range, as shown in FIGS. 7(A) and 7(B), possibly resultingin warping of the illumination range, which causes the illuminationrange to shift out of the image forming range of the liquid crystaldevice. Also, if such warping in the illumination range occurs, theilluminance at the left side and the illuminance at the right sidebecome uneven, which prevents the advantages of using the polarizationillumination device 1.

The projection-type display apparatus 2000 of the present embodiment notonly provides for the aforementioned fine adjustment of each of theoptical components of the aforementioned polarization illuminationdevice 1, but also the angles of the reflecting surfaces of thereflecting mirrors 943 and 972 which are disposed in the optical pathsof the light fluxes of each color can be subjected to fine adjustment asto the incident optical axis around an axial line (following the arrowsin FIG. 9) vertical to a plane including the incident optical axis andreflected optical axis. Also, the attachment position of theintermediate lens 973 attached between the reflecting mirrors 971 and972 can be adjusted vertically and horizontally. An angle adjustingmechanism for the attachment angle of the reflecting surface of thereflecting mirror is described with reference to FIG. 8.

Although transmittance-type liquid crystal light valves are used for theliquid crystal light valves 925R, 925G, and 925B in the above-describedtwo examples, the invention can also be applied to projection-typedisplay apparatuses using reflectance-type liquid crystal devices.Accordingly, the following is a description of one example of aprojection-type display apparatus using reflectance-type liquid crystallight valves instead of transmittance-type liquid crystal light valvesin the above-described projection-type display apparatus 2000. In theprojection-type display apparatus 3000 of the present invention, thecomponents which are the same as those in the above-describedprojection-type display apparatus 2000 are provided with the samereference numerals as those of FIG. 9-11, and detailed descriptionthereof is omitted.

FIG. 12 shows the principal components of the optical system of theprojection-type display apparatus 3000 in accordance with the invention.FIG. 12 is a cross-sectional view on the X-Z plane passing through thecenter of the second optical component 300.

The polarization beam splitter 400 includes a prism having anS-polarization light flux reflecting surface 401 which reflectsS-polarization light flux at approximately 450 and allows transmittanceof P-polarization light flux. Since the light flux emitted from thesecond optical component 300 is light flux which has been converted inone type of polarization direction, almost all of the light flux iseither reflected or transmitted by the polarization beam splitter 400.In accordance with the present embodiment, the light flux emitted fromthe second optical component 300 is S-polarization light flux, thisS-polarization light flux being bent 90° by the S-polarization lightflux reflecting surface 401 and cast into a prism unit 500 whereindichroic films have been adhered one to another in an X-like form,wherein the light flux is separated into the three colors, R, G, and B.Each of the separated light components is cast into reflectance-typeliquid crystal devices 600R, 600G, and 600B, which are providedfollowing the three sides of the dichroic prism 500. The light flux castinto the reflectance-type liquid crystal devices 600R, 600G, and 600B ismodulated by the reflectance-type liquid crystal devices 600R, 600G, and600B.

FIG. 13 shows an example of the reflectance-type liquid crystal devices600R, 600G, and 600B. The reflectance-type liquid crystal devices 600R,600G, and 600B are active-matrix type liquid crystal devices, whereinTFT switching devices are connected to each of the devices arrayed in amatrix, and a liquid Crystal layer 620 is sandwiched between a pair ofsubstrates, 610 and 630. The substrate 610 is formed of silicone, andformed to a portion thereof is the source 611 and drain 616. Also,formed upon the substrate 610 are a source electrode 612 and drainelectrode 617 formed of an aluminum layer, channels formed of siliconedioxide layer 613, gate electrodes formed of a silicone layer 614 and atantalum layer 615, inter-layer insulating film 618, and a reflectancepicture element electrode 619 formed of an aluminum layer, wherein thedrain electrode 617 and reflectance picture element electrode 619 areelectrically connected by a contact hole H. Since the reflectancepicture element electrode 619 is non-transparent, it can be laid overthe gate electrode, source electrode 612, and drain electrode 617 viathe inter-layer insulating film 618. Since the distance X between theneighboring reflectance picture element electrodes 619 can be quitesmall, the opening ratio can be great, so that the projected image canbe bright. Incidentally, in the present embodiment, holding capacity isprovided that includes drain 616, silicone dioxide layer 613′, siliconelayer 614′, and tantalum layer 615.

On the other hand, an opposing electrode 631 which is formed of ITO isdisposed on the surface of one side of the opposing substrate 630adjacent to the liquid crystal layer 620. An anti-reflection layer 632is disposed on the other surface of the opposing substrate 630. Theliquid crystal layer 620 of the present embodiment is such that theliquid crystal molecules 621 are vertically aligned when OFF-voltage isapplied (OFF-state), and the liquid crystal molecules 621 exhibit superhomeotropic orientation and twist 90° when ON-voltage is applied(ON-state). Accordingly, as shown in FIG. 4, the S-polarization lightflux which is cast to the reflectance-type liquid crystal devices 600R,600G, and 600B from the polarization beam splitter 400 when OFF-voltageis applied is returned from the reflectance-type liquid crystal devices600R, 600G, and 600B to the polarization beam splitter 400 without anychange in the polarization direction thereof. Thus, the S-polarizationlight flux is not reflected by the S-polarization light flux reflectingsurface 401 and does not reach the side of the projecting lens unit 6.On the other hand, the S-polarization light flux cast to thereflectance-type liquid crystal devices 600R, 600G, and 600B from thepolarization beam splitter 400 when voltage (ON) is applied becomesP-polarization light flux with the polarization direction thereofchanged due to twisting of the liquid crystal molecules 621, istransmitted through the S-polarization light flux reflecting surface401, and is subsequently projected onto the screen 100 via theprojection lens unit 6.

The following description is made with reference to FIG. 12. The lightflux modulated by the reflectance-type liquid crystal devices 600R,600G, and 600B is synthesized by the prism unit 500, and is subsequentlyprojected onto the screen 100 via the polarization beam splitter 400 andprojection lens unit 6.

Also, in accordance with the projection-type display apparatus 3000 ofthe present embodiment as well, making the attachment position of thefirst optical component 200 and second optical component 300 of thepolarization converting device 20 of the polarization illuminationdevice 1 to be movable vertically and horizontally in directionsorthogonally intersecting the light axis enables the illumination rangeof the liquid crystal devices of this polarization illumination device 1to be adjusted into the appropriate position and form. The positionadjusting mechanism of the above-described position-adjustable opticalcomponents, the adjustment method thereof, and the effects and so forthobtained by adjusting the illumination range are the same as those ofthe above-described projection-type display apparatus 2000.

Also, in accordance with the projection-type display apparatus 3000 ofthe present embodiment, not only can the same effects of the other twoprojection-type display apparatuses described above be obtained otherthan by adjustment of the illumination area, but the following effectscan also be obtained. Since the color separating device and the colorsynthesizing device are incorporated in a single prism unit, the opticalpath can be made to be extremely short. Also, since the opening ratio ofthe liquid crystal device is great, loss of light can be prevented.Accordingly, a bright projected image can be obtained even without usinga projecting lens with a great diameter. Further, by using the firstoptical component and second optical component, polarized light fluxwhich is uniform in brightness and without irregularity can be obtainedas illumination light, and thus a projected image can be obtained whichis extremely uniform over the display surface and the overall projectionsurface is also extremely bright.

Further, while in the present embodiment, reflectance-type liquidcrystal devices 600R, 600G, and 600B are used as reflectance-typemodulating devices, reflectance-type modulating devices other thanliquid crystal devices can also be used, and the structure thereof, thematerials of each component, and the operation mode of the liquidcrystal layer 620 are not limited to that of the above-describedexample.

Further, forming the prism 402 of the polarization beam splitter 400 andthe prism 501 of the prisms unit 500 as a single prism prevents lightloss at these borders, further increasing efficiency of light usage.

Although the above-described three examples are fine adjustmentmechanisms for optical components in projection-type display apparatusescapable of projecting color images, such fine adjustment mechanisms canalso be applied to projection-type display apparatuses which arearranged to project monochrome images.

Also, the arrangement of the optical system is not restricted to theabove described examples either, and altering the arrangement of thedevices does not necessarily obviate the advantages of the invention.

Further, regarding projection-type display apparatuses, there are rearprojection-type display apparatuses which project images from theopposite side of the observation side of the screen, in addition to thefrontal projection type display apparatuses described in the presentembodiment wherein images are projected from the observation side of thescreen. The present invention is also applicable to such rear-projectiontypes.

As described above, the projection-type display apparatuses inaccordance with the invention provide fine adjustment of the attachmentposition of each of the lens plate of the integrator optical system. Inaddition to, or instead of this fine adjustment, the invention providesfine adjustment of the attachment angle of the reflecting deviceprovided on the optical path extending from the light source to themodulation device. Accordingly, the formation position of theillumination range of illuminating light illuminating the modulatingdevice can be subjected to fine adjustment in the direction vertical tothe optical axis, and thereby the image forming position of theillumination range can be set so as to include the image forming rangeof the modulation device at all times.

Thus, there is no need to provide a wide margin around the imageformation area, taking shifting of the illumination range from the imageforming range of the modulation device into consideration. Accordingly,effectiveness of the illumination light usage can be increased,consequently improving the brightness of the projected image. Also, theillumination range of illumination light is formed so as to include theimage forming range, which obviates problems such as shadows forming onthe edge of the projected image.

What is claimed is:
 1. A projector having an optical axis, comprising: alight source that emits light; a modulating device that modulates thelight emitted from the light source in accordance with image signals; aprojecting lens that projects the light modulated by the modulatingdevice; a first lens plate and a second lens plate, each including aplurality of lenses arrayed in a matrix disposed in an optical pathbetween the light source and the modulating device; an interface boardincluding an input/output interface circuit; a mounted video boardincluding a video signal processing circuit; a control board that drivesand controls the projector; and an outer casing that accommodates thelight source, the modulating device, the first lens plate, the secondlens plate, the interface board, the video board, and the control board,at least one of the first lens plate and the second lens plate beingarranged so that an attachment position thereof is adjustable in adirection intersecting the optical axis of the projector.
 2. A projectorhaving an optical axis, comprising: a light source that emits lights; afirst optical component that splits the emitted lights from the lightsource into a plurality of intermediate lights, the intermediate lightsbeing focused at a position; a second optical component disposed inproximity to the position at which the intermediate lights are focused;a modulating device that modulates light emitted from the second opticalcomponent; a projecting lens that projects the light modulated by themodulating device; an interface board including an input/outputinterface circuit; a mounted video board including a video signalprocessing circuit; a control board that drives and controls theprojector; and an outer casing that accommodates the light source, themodulating device, the first lens plate, the second lens plate, theinterface board, the video board, and the control board, the secondoptical component including: a focusing lens array that focuses each ofthe plurality of intermediate lights split by the first opticalcomponent; a polarization converting device which spatially splits eachof the plurality of intermediate lights focused by the focusing lensarray into P-polarization light and S-polarization light, and whichemits the P-polarization light and S-polarization light with apolarization direction of one matching a polarization direction ofanother; and a combining lens for superimposing the lights emitted fromthe polarization converting device, at least one of the first opticalcomponent and the second optical component being arranged so that anattachment position thereof is adjustable in a direction intersectingthe optical axis of the projector.
 3. A projector having an opticalaxis, comprising: a light source that emits light; a modulating devicethat modulates the light emitted from the light source in accordancewith image signals; a projecting lens that projects the light modulatedby the modulating device; a first lens plate and a second lens plate,each including a plurality of lenses arrayed in a matrix disposed in anoptical path between the light source and the modulating device; anadjusting mechanism that adjusts an attachment position of at least oneof the first lens plate and the second lens plate in a directionintersecting the optical axis of the projector; an interface boardincluding an input/output interface circuit; a mounted video boardincluding a video signal processing circuit; a control board that drivesand controls the projector; and an outer casing that accommodates thelight source, the modulating device, the first lens plate, the secondlens plate, the adjusting mechanism, the interface board, the videoboard, and the control board.
 4. A projector having an optical axis,comprising: a light source that emits lights; a first optical componentthat splits the emitted lights from the light source into a plurality ofintermediate lights, the intermediate lights being focused at aposition; a second optical component placed in proximity to the positionat which the intermediate lights are focused, the second opticalcomponent including a focusing lens that focuses each of the pluralityof intermediate lights split by the first optical component; apolarization converting device which spatially splits each of theplurality of intermediate lights focused by the focusing lens array intoP-polarization light and S-polarization light, and which emits theP-polarization light and S-polarization light with a polarizationdirection of one matching a polarization direction of another; and acombining lens for superimposing lights emitted from the polarizationconverting device; a modulating device that modulates light emitted fromthe second optical component; a projecting lens that projects the lightmodulated by the modulating device; an adjusting mechanism that adjustsan attachment position of at least one of the first optical componentand the second optical component in a direction intersecting the opticalaxis of the projector; an interface board including an input/outputinterface circuit; a mounted video board including a video signalprocessing circuit; a control board that drives and controls theprojector; and an outer casing that accommodates the light source, themodulating device, the first optical component, the second opticalcomponent, the adjusting mechanism, the interface board, the videoboard, and the control board.
 5. A projector having an optical axis,comprising: a light source that emits light; a modulating device thatmodulates light emitted from the light source; a projecting lens thatprojects the light modulated by the modulating device; a reflectingdevice provided in an optical path between the light source and themodulating device; an adjusting mechanism that adjusts an attachmentposition of the reflecting device; a light guide that stores thereflecting device; an interface board including an input/outputinterface circuit; a mounted video board including a video signalprocessing circuit; a control board that drives and controls theprojector; and an outer casing that accommodates the light source, themodulating device, the reflecting device, the adjusting mechanism, thelight guide, the interface board, the video board, and the controlboard, the adjusting mechanism further including: a holder plate whichholds the reflecting device and is rotatably supported by the lightguide; a screw that adjusts an angle of the reflecting device; and aspring that supports the holder plate as to the light guide.
 6. Aprojector having an optical axis, comprising: a light source that emitslight; a color separating optical system that separates the emittedlight from the light source into lights of three colors; threemodulating devices that modulate the light emitted from the lightsource; a color synthesizing system that synthesizes light of each colormodulated by the three modulating devices; a projecting lens thatprojects the light modulated by the three modulating devices; areflecting device provided in an optical path between the colorseparating optical system and at least one of the three modulatingdevices; an adjusting mechanism that adjusts an attachment position ofthe reflecting device; a light guide that stores the reflecting device;an interface board including an input/output interface circuit; a videoboard mounted including a video signal processing circuit; a controlboard that drives and controls the projector; and an outer casing thataccommodates the light source, the color separating optical system, thethree modulating devices, the color synthesizing system, the reflectingdevice, the adjusting mechanism, the light guide, the interface board,the video board, and the control board, the adjusting mechanism furtherincluding: a holder plate which holds the reflecting device and isrotatably supported by the light guide; a screw that adjusts an angle ofthe reflecting device; and a spring that supports the holder plate as tothe light guide.